prod/doc/setup.hmac: filled the intro sections; added dfu-util installation
prod/doc/setup.hmac: filled the intro sections; added dfu-util installation

cfriedt/ben-wpan,cfriedt/ben-wpan,cfriedt/ben-wpan,cfriedt/ben-wpan,cfriedt/ben-wpan,cfriedt/ben-wpan